江苏沿海沙脊群表层沉积物Pb同位素特征及对物源的指示

Pb isotope characteristics and source implications of surface sediments in sand ridges of the Jiangsu Coast

为进一步查明江苏沿海沙脊群沉积物的来源,分析了该区域沉积物酸不溶组分Pb同位素特征。结果表明,远岸沙脊群陆向区域沉积物Pb同位素比值与近岸沙脊群相似,暗示其在潮波作用下有向岸运移的趋势。铅钕同位素分析揭示长江及周边河流沉积物在长江冲淡水和东海沿岸流作用下输移至远岸沙脊群海向区域。在苏北沿岸流作用下,老黄河三角洲沉积物输入对近岸沙脊群及远岸沙脊群陆向区域有影响;相反,诸如现代黄河口、济州岛和韩国河流等地沉积物输入对江苏沿海沙脊群的影响较弱。

In order to explore the sources of surface sediments in sand ridges of the Jiangsu Coast,the lead(Pb)isotope characteristics of acid-insoluble sediments in the sand ridges of the Jiangsu Coast were analyzed.The results showed that the Pb isotope ratios of landward sediments in the offshore sand ridges were similar to those in the onshore sand ridges,indicating a landward migration trend of sediments under the action of tidal waves.Pb and neodymium(Nd)isotope analyses revealed that the sediments of the Yangtze River and surrounding rivers were transported to the seaward area of the offshore sand ridges under the action of the Yangtze River diluted water and the East China Sea coastal current.The sediment input from the Old Yellow River Delta had an impact on the onshore sand ridges and the landward area of offshore sand ridges under the action of the Subei coastal current.On the contrary,the impacts of sediment input from the Modern Yellow River Delta,Jeju Island and Korean rivers were weak on the sand ridges of the Jiangsu Coast.